// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
package qunar.tc.decompiler.struct.attr;

import qunar.tc.decompiler.struct.consts.ConstantPool;
import qunar.tc.decompiler.util.DataInputFullStream;
import qunar.tc.decompiler.util.InterpreterUtil;

import java.io.IOException;

/**
 * u2 line_number_table_length;
 * {  u2 start_pc;
 * u2 line_number;
 * } line_number_table[line_number_table_length];
 * <p>
 * Created by Egor on 05.10.2014.
 */
public class StructLineNumberTableAttribute extends StructGeneralAttribute {
    private int[] myLineInfo = InterpreterUtil.EMPTY_INT_ARRAY;

    @Override
    public void initContent(DataInputFullStream data, ConstantPool pool) throws IOException {
        int len = data.readUnsignedShort() * 2;
        if (len > 0) {
            myLineInfo = new int[len];
            for (int i = 0; i < len; i += 2) {
                myLineInfo[i] = data.readUnsignedShort();
                myLineInfo[i + 1] = data.readUnsignedShort();
            }
        } else if (myLineInfo.length > 0) {
            myLineInfo = InterpreterUtil.EMPTY_INT_ARRAY;
        }
    }

    public int findLineNumber(int pc) {
        if (myLineInfo.length >= 2) {
            for (int i = myLineInfo.length - 2; i >= 0; i -= 2) {
                if (pc >= myLineInfo[i]) {
                    return myLineInfo[i + 1];
                }
            }
        }
        return -1;
    }

    public int[] getRawData() {
        return myLineInfo;
    }
}